The plBytesRead parameter value might differ from the actual number of bytes read from the file in the case of translations.

Compound files are not supported by the mmioGetHeader function. Only non-compound files and compound-file elements are supported.

This function can be used in conjunction with the mmioSet function to query specific track headers from a multiple track movie file.

If the length passed in was not large enough to hold the header, MMIOERR_INVALID_BUFFER_LENGTH is set in ulErrorRet. If the header is in error, MMIOERR_INVALID_STRUCTURE is set in ulErrorRet.